]> git.sesse.net Git - bcachefs-tools-debian/blobdiff - libbcachefs/btree_update_interior.c
Update bcachefs sources to 24bdb6fed91c bcachefs: bch2_btree_id_str()
[bcachefs-tools-debian] / libbcachefs / btree_update_interior.c
index dac2fa6b08ee2f4b23b8fd1874e4026e2b14a4dc..7dbf6b6c7f3481e0d0ab0e15b9b5ec6c501131f0 100644 (file)
@@ -5,23 +5,24 @@
 #include "bkey_methods.h"
 #include "btree_cache.h"
 #include "btree_gc.h"
+#include "btree_journal_iter.h"
 #include "btree_update.h"
 #include "btree_update_interior.h"
 #include "btree_io.h"
 #include "btree_iter.h"
 #include "btree_locking.h"
 #include "buckets.h"
+#include "clock.h"
 #include "error.h"
 #include "extents.h"
 #include "journal.h"
 #include "journal_reclaim.h"
 #include "keylist.h"
-#include "recovery.h"
 #include "replicas.h"
 #include "super-io.h"
+#include "trace.h"
 
 #include <linux/random.h>
-#include <trace/events/bcachefs.h>
 
 static int bch2_btree_insert_node(struct btree_update *, struct btree_trans *,
                                  struct btree_path *, struct btree *,
@@ -72,7 +73,7 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
                        break;
                bp = bkey_s_c_to_btree_ptr_v2(k);
 
-               if (bpos_cmp(next_node, bp.v->min_key)) {
+               if (!bpos_eq(next_node, bp.v->min_key)) {
                        bch2_dump_btree_node(c, b);
                        bch2_bpos_to_text(&buf1, next_node);
                        bch2_bpos_to_text(&buf2, bp.v->min_key);
@@ -82,7 +83,7 @@ static void btree_node_interior_verify(struct bch_fs *c, struct btree *b)
                bch2_btree_node_iter_advance(&iter, b);
 
                if (bch2_btree_node_iter_end(&iter)) {
-                       if (bpos_cmp(k.k->p, b->key.k.p)) {
+                       if (!bpos_eq(k.k->p, b->key.k.p)) {
                                bch2_dump_btree_node(c, b);
                                bch2_bpos_to_text(&buf1, b->key.k.p);
                                bch2_bpos_to_text(&buf2, k.k->p);
@@ -142,10 +143,15 @@ static size_t btree_node_u64s_with_format(struct btree *b,
 }
 
 /**
- * btree_node_format_fits - check if we could rewrite node with a new format
+ * bch2_btree_node_format_fits - check if we could rewrite node with a new format
  *
- * This assumes all keys can pack with the new format -- it just checks if
- * the re-packed keys would fit inside the node itself.
+ * @c:         filesystem handle
+ * @b:         btree node to rewrite
+ * @new_f:     bkey format to translate keys to
+ *
+ * Returns: true if all re-packed keys will be able to fit in a new node.
+ *
+ * Assumes all keys will successfully pack with the new format.
  */
 bool bch2_btree_node_format_fits(struct bch_fs *c, struct btree *b,
                                 struct bkey_format *new_f)
@@ -161,6 +167,7 @@ static void __btree_node_free(struct bch_fs *c, struct btree *b)
 {
        trace_and_count(c, btree_node_free, c, b);
 
+       BUG_ON(btree_node_write_blocked(b));
        BUG_ON(btree_node_dirty(b));
        BUG_ON(btree_node_need_write(b));
        BUG_ON(b == btree_node_root(c, b));
@@ -186,7 +193,7 @@ static void bch2_btree_node_free_inmem(struct btree_trans *trans,
        bch2_btree_node_hash_remove(&c->btree_cache, b);
        __btree_node_free(c, b);
        six_unlock_write(&b->c.lock);
-       mark_btree_node_locked_noreset(path, level, SIX_LOCK_intent);
+       mark_btree_node_locked_noreset(path, level, BTREE_NODE_INTENT_LOCKED);
 
        trans_for_each_path(trans, path)
                if (path->l[level].b == b) {
@@ -241,27 +248,21 @@ static struct btree *__bch2_btree_node_alloc(struct btree_trans *trans,
        struct bch_fs *c = trans->c;
        struct write_point *wp;
        struct btree *b;
-       __BKEY_PADDED(k, BKEY_BTREE_PTR_VAL_U64s_MAX) tmp;
-       struct open_buckets ob = { .nr = 0 };
+       BKEY_PADDED_ONSTACK(k, BKEY_BTREE_PTR_VAL_U64s_MAX) tmp;
+       struct open_buckets obs = { .nr = 0 };
        struct bch_devs_list devs_have = (struct bch_devs_list) { 0 };
-       unsigned nr_reserve;
-       enum alloc_reserve alloc_reserve;
+       enum bch_watermark watermark = flags & BCH_WATERMARK_MASK;
+       unsigned nr_reserve = watermark > BCH_WATERMARK_reclaim
+               ? BTREE_NODE_RESERVE
+               : 0;
        int ret;
 
-       if (flags & BTREE_INSERT_USE_RESERVE) {
-               nr_reserve      = 0;
-               alloc_reserve   = RESERVE_btree_movinggc;
-       } else {
-               nr_reserve      = BTREE_NODE_RESERVE;
-               alloc_reserve   = RESERVE_btree;
-       }
-
        mutex_lock(&c->btree_reserve_cache_lock);
        if (c->btree_reserve_cache_nr > nr_reserve) {
                struct btree_alloc *a =
                        &c->btree_reserve_cache[--c->btree_reserve_cache_nr];
 
-               ob = a->ob;
+               obs = a->ob;
                bkey_copy(&tmp.k, &a->k);
                mutex_unlock(&c->btree_reserve_cache_lock);
                goto mem_alloc;
@@ -277,7 +278,7 @@ retry:
                                      &devs_have,
                                      res->nr_replicas,
                                      c->opts.metadata_replicas_required,
-                                     alloc_reserve, 0, cl, &wp);
+                                     watermark, 0, cl, &wp);
        if (unlikely(ret))
                return ERR_PTR(ret);
 
@@ -296,10 +297,10 @@ retry:
        bkey_btree_ptr_v2_init(&tmp.k);
        bch2_alloc_sectors_append_ptrs(c, wp, &tmp.k, btree_sectors(c), false);
 
-       bch2_open_bucket_get(c, wp, &ob);
+       bch2_open_bucket_get(c, wp, &obs);
        bch2_alloc_sectors_done(c, wp);
 mem_alloc:
-       b = bch2_btree_node_mem_alloc(c, interior_node);
+       b = bch2_btree_node_mem_alloc(trans, interior_node);
        six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
 
@@ -308,7 +309,7 @@ mem_alloc:
        BUG_ON(b->ob.nr);
 
        bkey_copy(&b->key, &tmp.k);
-       b->ob = ob;
+       b->ob = obs;
 
        return b;
 }
@@ -362,6 +363,7 @@ static struct btree *bch2_btree_node_alloc(struct btree_update *as,
        BUG_ON(ret);
 
        trace_and_count(c, btree_node_alloc, c, b);
+       bch2_increment_clock(c, btree_sectors(c), WRITE);
        return b;
 }
 
@@ -378,14 +380,19 @@ static void btree_set_max(struct btree *b, struct bpos pos)
        b->data->max_key = pos;
 }
 
-struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
-                                                 struct btree_trans *trans,
-                                                 struct btree *b,
-                                                 struct bkey_format format)
+static struct btree *bch2_btree_node_alloc_replacement(struct btree_update *as,
+                                                      struct btree_trans *trans,
+                                                      struct btree *b)
 {
-       struct btree *n;
+       struct btree *n = bch2_btree_node_alloc(as, trans, b->c.level);
+       struct bkey_format format = bch2_btree_calc_format(b);
 
-       n = bch2_btree_node_alloc(as, trans, b->c.level);
+       /*
+        * The keys might expand with the new format - if they wouldn't fit in
+        * the btree node anymore, use the old format for now:
+        */
+       if (!bch2_btree_node_format_fits(as->c, b, &format))
+               format = b->format;
 
        SET_BTREE_NODE_SEQ(n->data, BTREE_NODE_SEQ(b->data) + 1);
 
@@ -398,27 +405,9 @@ struct btree *__bch2_btree_node_alloc_replacement(struct btree_update *as,
        bch2_btree_sort_into(as->c, n, b);
 
        btree_node_reset_sib_u64s(n);
-
-       n->key.k.p = b->key.k.p;
        return n;
 }
 
-static struct btree *bch2_btree_node_alloc_replacement(struct btree_update *as,
-                                                      struct btree_trans *trans,
-                                                      struct btree *b)
-{
-       struct bkey_format new_f = bch2_btree_calc_format(b);
-
-       /*
-        * The keys might expand with the new format - if they wouldn't fit in
-        * the btree node anymore, use the old format for now:
-        */
-       if (!bch2_btree_node_format_fits(as->c, b, &new_f))
-               new_f = b->format;
-
-       return __bch2_btree_node_alloc_replacement(as, trans, b, new_f);
-}
-
 static struct btree *__btree_root_alloc(struct btree_update *as,
                                struct btree_trans *trans, unsigned level)
 {
@@ -608,12 +597,11 @@ static void btree_update_nodes_written(struct btree_update *as)
 {
        struct bch_fs *c = as->c;
        struct btree *b;
-       struct btree_trans trans;
+       struct btree_trans *trans = bch2_trans_get(c);
        u64 journal_seq = 0;
        unsigned i;
        int ret;
 
-       bch2_trans_init(&trans, c, 0, 512);
        /*
         * If we're already in an error state, it might be because a btree node
         * was never written, and we might be trying to free that same btree
@@ -634,7 +622,7 @@ static void btree_update_nodes_written(struct btree_update *as)
 
                b = as->old_nodes[i];
 
-               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
+               btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_read);
                seq = b->data ? b->data->keys.seq : 0;
                six_unlock_read(&b->c.lock);
 
@@ -656,14 +644,13 @@ static void btree_update_nodes_written(struct btree_update *as)
         * journal reclaim does btree updates when flushing bkey_cached entries,
         * which may require allocations as well.
         */
-       ret = commit_do(&trans, &as->disk_res, &journal_seq,
+       ret = commit_do(trans, &as->disk_res, &journal_seq,
+                       BCH_WATERMARK_reclaim|
                        BTREE_INSERT_NOFAIL|
                        BTREE_INSERT_NOCHECK_RW|
-                       BTREE_INSERT_USE_RESERVE|
-                       BTREE_INSERT_JOURNAL_RECLAIM|
-                       JOURNAL_WATERMARK_reserved,
-                       btree_update_nodes_written_trans(&trans, as));
-       bch2_trans_unlock(&trans);
+                       BTREE_INSERT_JOURNAL_RECLAIM,
+                       btree_update_nodes_written_trans(trans, as));
+       bch2_trans_unlock(trans);
 
        bch2_fs_fatal_err_on(ret && !bch2_journal_error(&c->journal), c,
                             "%s(): error %s", __func__, bch2_err_str(ret));
@@ -672,7 +659,7 @@ err:
                struct btree_path *path;
 
                b = as->b;
-               path = get_unlocked_mut_path(&trans, as->btree_id, b->c.level, b->key.k.p);
+               path = get_unlocked_mut_path(trans, as->btree_id, b->c.level, b->key.k.p);
                /*
                 * @b is the node we did the final insert into:
                 *
@@ -695,12 +682,13 @@ err:
                 * we may rarely end up with a locked path besides the one we
                 * have here:
                 */
-               bch2_trans_unlock(&trans);
-               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_intent);
-               mark_btree_node_locked(&trans, path, b->c.level, SIX_LOCK_intent);
-               bch2_btree_path_level_init(&trans, path, b);
+               bch2_trans_unlock(trans);
+               btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path, b->c.level, BTREE_NODE_INTENT_LOCKED);
+               path->l[b->c.level].lock_seq = six_lock_seq(&b->c.lock);
+               path->l[b->c.level].b = b;
 
-               bch2_btree_node_lock_write_nofail(&trans, path, &b->c);
+               bch2_btree_node_lock_write_nofail(trans, path, &b->c);
 
                mutex_lock(&c->btree_interior_update_lock);
 
@@ -713,15 +701,15 @@ err:
                 * btree_interior_update_lock:
                 */
                if (as->b == b) {
-                       struct bset *i = btree_bset_last(b);
-
                        BUG_ON(!b->c.level);
                        BUG_ON(!btree_node_dirty(b));
 
                        if (!ret) {
-                               i->journal_seq = cpu_to_le64(
+                               struct bset *last = btree_bset_last(b);
+
+                               last->journal_seq = cpu_to_le64(
                                                             max(journal_seq,
-                                                                le64_to_cpu(i->journal_seq)));
+                                                                le64_to_cpu(last->journal_seq)));
 
                                bch2_btree_add_journal_pin(c, b, journal_seq);
                        } else {
@@ -736,12 +724,12 @@ err:
 
                mutex_unlock(&c->btree_interior_update_lock);
 
-               mark_btree_node_locked_noreset(path, b->c.level, SIX_LOCK_intent);
+               mark_btree_node_locked_noreset(path, b->c.level, BTREE_NODE_INTENT_LOCKED);
                six_unlock_write(&b->c.lock);
 
                btree_node_write_if_need(c, b, SIX_LOCK_intent);
-               btree_node_unlock(&trans, path, b->c.level);
-               bch2_path_put(&trans, path, true);
+               btree_node_unlock(trans, path, b->c.level);
+               bch2_path_put(trans, path, true);
        }
 
        bch2_journal_pin_drop(&c->journal, &as->journal);
@@ -761,7 +749,7 @@ err:
        for (i = 0; i < as->nr_new_nodes; i++) {
                b = as->new_nodes[i];
 
-               btree_node_lock_nopath_nofail(&trans, &b->c, SIX_LOCK_read);
+               btree_node_lock_nopath_nofail(trans, &b->c, SIX_LOCK_read);
                btree_node_write_if_need(c, b, SIX_LOCK_read);
                six_unlock_read(&b->c.lock);
        }
@@ -769,8 +757,8 @@ err:
        for (i = 0; i < as->nr_open_buckets; i++)
                bch2_open_bucket_put(c, c->open_buckets + as->open_buckets[i]);
 
-       bch2_btree_update_free(as, &trans);
-       bch2_trans_exit(&trans);
+       bch2_btree_update_free(as, trans);
+       bch2_trans_put(trans);
 }
 
 static void btree_interior_update_work(struct work_struct *work)
@@ -819,6 +807,7 @@ static void btree_update_updated_node(struct btree_update *as, struct btree *b)
 
        BUG_ON(as->mode != BTREE_INTERIOR_NO_UPDATE);
        BUG_ON(!btree_node_dirty(b));
+       BUG_ON(!b->c.level);
 
        as->mode        = BTREE_INTERIOR_UPDATING_NODE;
        as->b           = b;
@@ -988,6 +977,7 @@ static void bch2_btree_interior_update_will_free_node(struct btree_update *as,
 
        clear_btree_node_dirty_acct(c, b);
        clear_btree_node_need_write(b);
+       clear_btree_node_write_blocked(b);
 
        /*
         * Does this node have unwritten data that has a pin on the journal?
@@ -1056,14 +1046,24 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
                ? BCH_DISK_RESERVATION_NOFAIL : 0;
        unsigned nr_nodes[2] = { 0, 0 };
        unsigned update_level = level;
-       int journal_flags = flags & JOURNAL_WATERMARK_MASK;
+       enum bch_watermark watermark = flags & BCH_WATERMARK_MASK;
+       unsigned journal_flags = 0;
        int ret = 0;
        u32 restart_count = trans->restart_count;
 
        BUG_ON(!path->should_be_locked);
 
+       if (watermark == BCH_WATERMARK_copygc)
+               watermark = BCH_WATERMARK_btree_copygc;
+       if (watermark < BCH_WATERMARK_btree)
+               watermark = BCH_WATERMARK_btree;
+
+       flags &= ~BCH_WATERMARK_MASK;
+       flags |= watermark;
+
        if (flags & BTREE_INSERT_JOURNAL_RECLAIM)
                journal_flags |= JOURNAL_RES_GET_NONBLOCK;
+       journal_flags |= watermark;
 
        while (1) {
                nr_nodes[!!update_level] += 1 + split;
@@ -1084,22 +1084,20 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
                                        BKEY_BTREE_PTR_U64s_MAX * (1 + split)))
                        break;
 
-               split = true;
+               split = path->l[update_level].b->nr.live_u64s > BTREE_SPLIT_THRESHOLD(c);
        }
 
        if (flags & BTREE_INSERT_GC_LOCK_HELD)
                lockdep_assert_held(&c->gc_lock);
        else if (!down_read_trylock(&c->gc_lock)) {
-               bch2_trans_unlock(trans);
-               down_read(&c->gc_lock);
-               ret = bch2_trans_relock(trans);
+               ret = drop_locks_do(trans, (down_read(&c->gc_lock), 0));
                if (ret) {
                        up_read(&c->gc_lock);
                        return ERR_PTR(ret);
                }
        }
 
-       as = mempool_alloc(&c->btree_interior_update_pool, GFP_NOIO);
+       as = mempool_alloc(&c->btree_interior_update_pool, GFP_NOFS);
        memset(as, 0, sizeof(*as));
        closure_init(&as->cl, NULL);
        as->c           = c;
@@ -1135,23 +1133,19 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
                                      BTREE_UPDATE_JOURNAL_RES,
                                      journal_flags|JOURNAL_RES_GET_NONBLOCK);
        if (ret) {
-               bch2_trans_unlock(trans);
-
                if (flags & BTREE_INSERT_JOURNAL_RECLAIM) {
                        ret = -BCH_ERR_journal_reclaim_would_deadlock;
                        goto err;
                }
 
-               ret = bch2_journal_preres_get(&c->journal, &as->journal_preres,
+               ret = drop_locks_do(trans,
+                       bch2_journal_preres_get(&c->journal, &as->journal_preres,
                                              BTREE_UPDATE_JOURNAL_RES,
-                                             journal_flags);
-               if (ret) {
+                                             journal_flags));
+               if (ret == -BCH_ERR_journal_preres_get_blocked) {
                        trace_and_count(c, trans_restart_journal_preres_get, trans, _RET_IP_, journal_flags);
                        ret = btree_trans_restart(trans, BCH_ERR_transaction_restart_journal_preres_get);
-                       goto err;
                }
-
-               ret = bch2_trans_relock(trans);
                if (ret)
                        goto err;
        }
@@ -1168,6 +1162,17 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
            bch2_err_matches(ret, ENOMEM)) {
                struct closure cl;
 
+               /*
+                * XXX: this should probably be a separate BTREE_INSERT_NONBLOCK
+                * flag
+                */
+               if (bch2_err_matches(ret, ENOSPC) &&
+                   (flags & BTREE_INSERT_JOURNAL_RECLAIM) &&
+                   watermark != BCH_WATERMARK_reclaim) {
+                       ret = -BCH_ERR_journal_reclaim_would_deadlock;
+                       goto err;
+               }
+
                closure_init_stack(&cl);
 
                do {
@@ -1175,7 +1180,7 @@ bch2_btree_update_start(struct btree_trans *trans, struct btree_path *path,
 
                        bch2_trans_unlock(trans);
                        closure_sync(&cl);
-               } while (ret == -EAGAIN);
+               } while (bch2_err_matches(ret, BCH_ERR_operation_blocked));
        }
 
        if (ret) {
@@ -1209,24 +1214,12 @@ static void bch2_btree_set_root_inmem(struct bch_fs *c, struct btree *b)
               (b->c.level < btree_node_root(c, b)->c.level ||
                !btree_node_dying(btree_node_root(c, b))));
 
-       btree_node_root(c, b) = b;
+       bch2_btree_id_root(c, b->c.btree_id)->b = b;
        mutex_unlock(&c->btree_root_lock);
 
        bch2_recalc_btree_reserve(c);
 }
 
-/**
- * bch_btree_set_root - update the root in memory and on disk
- *
- * To ensure forward progress, the current task must not be holding any
- * btree node write locks. However, you must hold an intent lock on the
- * old root.
- *
- * Note: This allocates a journal entry but doesn't add any keys to
- * it.  All the btree roots are part of every journal write, so there
- * is nothing new to be done.  This just guarantees that there is a
- * journal write.
- */
 static void bch2_btree_set_root(struct btree_update *as,
                                struct btree_trans *trans,
                                struct btree_path *path,
@@ -1271,6 +1264,7 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
        struct bch_fs *c = as->c;
        struct bkey_packed *k;
        struct printbuf buf = PRINTBUF;
+       unsigned long old, new, v;
 
        BUG_ON(insert->k.type == KEY_TYPE_btree_ptr_v2 &&
               !btree_ptr_sectors_written(insert));
@@ -1308,8 +1302,15 @@ static void bch2_insert_fixup_btree_ptr(struct btree_update *as,
 
        bch2_btree_bset_insert_key(trans, path, b, node_iter, insert);
        set_btree_node_dirty_acct(c, b);
-       set_btree_node_need_write(b);
-       b->write_type = BTREE_WRITE_interior;
+
+       v = READ_ONCE(b->flags);
+       do {
+               old = new = v;
+
+               new &= ~BTREE_WRITE_TYPE_MASK;
+               new |= BTREE_WRITE_interior;
+               new |= 1 << BTREE_NODE_need_write;
+       } while ((v = cmpxchg(&b->flags, old, new)) != old);
 
        printbuf_exit(&buf);
 }
@@ -1332,8 +1333,12 @@ __bch2_btree_insert_keys_interior(struct btree_update *as,
                ;
 
        while (!bch2_keylist_empty(keys)) {
-               bch2_insert_fixup_btree_ptr(as, trans, path, b,
-                               &node_iter, bch2_keylist_front(keys));
+               insert = bch2_keylist_front(keys);
+
+               if (bpos_gt(insert->k.p, b->key.k.p))
+                       break;
+
+               bch2_insert_fixup_btree_ptr(as, trans, path, b, &node_iter, insert);
                bch2_keylist_pop_front(keys);
        }
 }
@@ -1342,109 +1347,91 @@ __bch2_btree_insert_keys_interior(struct btree_update *as,
  * Move keys from n1 (original replacement node, now lower node) to n2 (higher
  * node)
  */
-static struct btree *__btree_split_node(struct btree_update *as,
-                                       struct btree_trans *trans,
-                                       struct btree *n1)
+static void __btree_split_node(struct btree_update *as,
+                              struct btree_trans *trans,
+                              struct btree *b,
+                              struct btree *n[2])
 {
-       struct bkey_format_state s;
-       size_t nr_packed = 0, nr_unpacked = 0;
-       struct btree *n2;
-       struct bset *set1, *set2;
-       struct bkey_packed *k, *set2_start, *set2_end, *out, *prev = NULL;
-       struct bpos n1_pos;
+       struct bkey_packed *k;
+       struct bpos n1_pos = POS_MIN;
+       struct btree_node_iter iter;
+       struct bset *bsets[2];
+       struct bkey_format_state format[2];
+       struct bkey_packed *out[2];
+       struct bkey uk;
+       unsigned u64s, n1_u64s = (b->nr.live_u64s * 3) / 5;
+       int i;
 
-       n2 = bch2_btree_node_alloc(as, trans, n1->c.level);
+       for (i = 0; i < 2; i++) {
+               BUG_ON(n[i]->nsets != 1);
 
-       n2->data->max_key       = n1->data->max_key;
-       n2->data->format        = n1->format;
-       SET_BTREE_NODE_SEQ(n2->data, BTREE_NODE_SEQ(n1->data));
-       n2->key.k.p = n1->key.k.p;
+               bsets[i] = btree_bset_first(n[i]);
+               out[i] = bsets[i]->start;
 
-       set1 = btree_bset_first(n1);
-       set2 = btree_bset_first(n2);
+               SET_BTREE_NODE_SEQ(n[i]->data, BTREE_NODE_SEQ(b->data) + 1);
+               bch2_bkey_format_init(&format[i]);
+       }
 
-       /*
-        * Has to be a linear search because we don't have an auxiliary
-        * search tree yet
-        */
-       k = set1->start;
-       while (1) {
-               struct bkey_packed *n = bkey_next(k);
+       u64s = 0;
+       for_each_btree_node_key(b, k, &iter) {
+               if (bkey_deleted(k))
+                       continue;
+
+               i = u64s >= n1_u64s;
+               u64s += k->u64s;
+               uk = bkey_unpack_key(b, k);
+               if (!i)
+                       n1_pos = uk.p;
+               bch2_bkey_format_add_key(&format[i], &uk);
+       }
 
-               if (n == vstruct_last(set1))
-                       break;
-               if (k->_data - set1->_data >= (le16_to_cpu(set1->u64s) * 3) / 5)
-                       break;
+       btree_set_min(n[0], b->data->min_key);
+       btree_set_max(n[0], n1_pos);
+       btree_set_min(n[1], bpos_successor(n1_pos));
+       btree_set_max(n[1], b->data->max_key);
 
-               if (bkey_packed(k))
-                       nr_packed++;
-               else
-                       nr_unpacked++;
+       for (i = 0; i < 2; i++) {
+               bch2_bkey_format_add_pos(&format[i], n[i]->data->min_key);
+               bch2_bkey_format_add_pos(&format[i], n[i]->data->max_key);
 
-               prev = k;
-               k = n;
+               n[i]->data->format = bch2_bkey_format_done(&format[i]);
+               btree_node_set_format(n[i], n[i]->data->format);
        }
 
-       BUG_ON(!prev);
-       set2_start      = k;
-       set2_end        = vstruct_last(set1);
-
-       set1->u64s = cpu_to_le16((u64 *) set2_start - set1->_data);
-       set_btree_bset_end(n1, n1->set);
+       u64s = 0;
+       for_each_btree_node_key(b, k, &iter) {
+               if (bkey_deleted(k))
+                       continue;
 
-       n1->nr.live_u64s        = le16_to_cpu(set1->u64s);
-       n1->nr.bset_u64s[0]     = le16_to_cpu(set1->u64s);
-       n1->nr.packed_keys      = nr_packed;
-       n1->nr.unpacked_keys    = nr_unpacked;
+               i = u64s >= n1_u64s;
+               u64s += k->u64s;
 
-       n1_pos = bkey_unpack_pos(n1, prev);
-       if (as->c->sb.version < bcachefs_metadata_version_snapshot)
-               n1_pos.snapshot = U32_MAX;
+               if (bch2_bkey_transform(&n[i]->format, out[i], bkey_packed(k)
+                                       ? &b->format: &bch2_bkey_format_current, k))
+                       out[i]->format = KEY_FORMAT_LOCAL_BTREE;
+               else
+                       bch2_bkey_unpack(b, (void *) out[i], k);
 
-       btree_set_max(n1, n1_pos);
-       btree_set_min(n2, bpos_successor(n1->key.k.p));
+               out[i]->needs_whiteout = false;
 
-       bch2_bkey_format_init(&s);
-       bch2_bkey_format_add_pos(&s, n2->data->min_key);
-       bch2_bkey_format_add_pos(&s, n2->data->max_key);
-
-       for (k = set2_start; k != set2_end; k = bkey_next(k)) {
-               struct bkey uk = bkey_unpack_key(n1, k);
-               bch2_bkey_format_add_key(&s, &uk);
+               btree_keys_account_key_add(&n[i]->nr, 0, out[i]);
+               out[i] = bkey_p_next(out[i]);
        }
 
-       n2->data->format = bch2_bkey_format_done(&s);
-       btree_node_set_format(n2, n2->data->format);
-
-       out = set2->start;
-       memset(&n2->nr, 0, sizeof(n2->nr));
-
-       for (k = set2_start; k != set2_end; k = bkey_next(k)) {
-               BUG_ON(!bch2_bkey_transform(&n2->format, out, bkey_packed(k)
-                                      ? &n1->format : &bch2_bkey_format_current, k));
-               out->format = KEY_FORMAT_LOCAL_BTREE;
-               btree_keys_account_key_add(&n2->nr, 0, out);
-               out = bkey_next(out);
-       }
+       for (i = 0; i < 2; i++) {
+               bsets[i]->u64s = cpu_to_le16((u64 *) out[i] - bsets[i]->_data);
 
-       set2->u64s = cpu_to_le16((u64 *) out - set2->_data);
-       set_btree_bset_end(n2, n2->set);
+               BUG_ON(!bsets[i]->u64s);
 
-       BUG_ON(!set1->u64s);
-       BUG_ON(!set2->u64s);
+               set_btree_bset_end(n[i], n[i]->set);
 
-       btree_node_reset_sib_u64s(n1);
-       btree_node_reset_sib_u64s(n2);
+               btree_node_reset_sib_u64s(n[i]);
 
-       bch2_verify_btree_nr_keys(n1);
-       bch2_verify_btree_nr_keys(n2);
+               bch2_verify_btree_nr_keys(n[i]);
 
-       if (n1->c.level) {
-               btree_node_interior_verify(as->c, n1);
-               btree_node_interior_verify(as->c, n2);
+               if (b->c.level)
+                       btree_node_interior_verify(as->c, n[i]);
        }
-
-       return n2;
 }
 
 /*
@@ -1464,41 +1451,16 @@ static void btree_split_insert_keys(struct btree_update *as,
                                    struct btree *b,
                                    struct keylist *keys)
 {
-       struct btree_node_iter node_iter;
-       struct bkey_i *k = bch2_keylist_front(keys);
-       struct bkey_packed *src, *dst, *n;
-       struct bset *i;
+       if (!bch2_keylist_empty(keys) &&
+           bpos_le(bch2_keylist_front(keys)->k.p, b->data->max_key)) {
+               struct btree_node_iter node_iter;
 
-       bch2_btree_node_iter_init(&node_iter, b, &k->k.p);
+               bch2_btree_node_iter_init(&node_iter, b, &bch2_keylist_front(keys)->k.p);
 
-       __bch2_btree_insert_keys_interior(as, trans, path, b, node_iter, keys);
+               __bch2_btree_insert_keys_interior(as, trans, path, b, node_iter, keys);
 
-       /*
-        * We can't tolerate whiteouts here - with whiteouts there can be
-        * duplicate keys, and it would be rather bad if we picked a duplicate
-        * for the pivot:
-        */
-       i = btree_bset_first(b);
-       src = dst = i->start;
-       while (src != vstruct_last(i)) {
-               n = bkey_next(src);
-               if (!bkey_deleted(src)) {
-                       memmove_u64s_down(dst, src, src->u64s);
-                       dst = bkey_next(dst);
-               }
-               src = n;
+               btree_node_interior_verify(as->c, b);
        }
-
-       /* Also clear out the unwritten whiteouts area: */
-       b->whiteout_u64s = 0;
-
-       i->u64s = cpu_to_le16((u64 *) dst - i->_data);
-       set_btree_bset_end(b, b->set);
-
-       BUG_ON(b->nsets != 1 ||
-              b->nr.live_u64s != le16_to_cpu(btree_bset_first(b)->u64s));
-
-       btree_node_interior_verify(as->c, b);
 }
 
 static int btree_split(struct btree_update *as, struct btree_trans *trans,
@@ -1517,15 +1479,21 @@ static int btree_split(struct btree_update *as, struct btree_trans *trans,
 
        bch2_btree_interior_update_will_free_node(as, b);
 
-       n1 = bch2_btree_node_alloc_replacement(as, trans, b);
+       if (b->nr.live_u64s > BTREE_SPLIT_THRESHOLD(c)) {
+               struct btree *n[2];
 
-       if (keys)
-               btree_split_insert_keys(as, trans, path, n1, keys);
-
-       if (bset_u64s(&n1->set[0]) > BTREE_SPLIT_THRESHOLD(c)) {
                trace_and_count(c, btree_node_split, c, b);
 
-               n2 = __btree_split_node(as, trans, n1);
+               n[0] = n1 = bch2_btree_node_alloc(as, trans, b->c.level);
+               n[1] = n2 = bch2_btree_node_alloc(as, trans, b->c.level);
+
+               __btree_split_node(as, trans, b, n);
+
+               if (keys) {
+                       btree_split_insert_keys(as, trans, path, n1, keys);
+                       btree_split_insert_keys(as, trans, path, n2, keys);
+                       BUG_ON(!bch2_keylist_empty(keys));
+               }
 
                bch2_btree_build_aux_trees(n2);
                bch2_btree_build_aux_trees(n1);
@@ -1537,12 +1505,12 @@ static int btree_split(struct btree_update *as, struct btree_trans *trans,
 
                path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
                six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
-               mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path1, n1->c.level, BTREE_NODE_INTENT_LOCKED);
                bch2_btree_path_level_init(trans, path1, n1);
 
                path2 = get_unlocked_mut_path(trans, path->btree_id, n2->c.level, n2->key.k.p);
                six_lock_increment(&n2->c.lock, SIX_LOCK_intent);
-               mark_btree_node_locked(trans, path2, n2->c.level, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path2, n2->c.level, BTREE_NODE_INTENT_LOCKED);
                bch2_btree_path_level_init(trans, path2, n2);
 
                /*
@@ -1563,7 +1531,7 @@ static int btree_split(struct btree_update *as, struct btree_trans *trans,
                        path2->locks_want++;
                        BUG_ON(btree_node_locked(path2, n3->c.level));
                        six_lock_increment(&n3->c.lock, SIX_LOCK_intent);
-                       mark_btree_node_locked(trans, path2, n3->c.level, SIX_LOCK_intent);
+                       mark_btree_node_locked(trans, path2, n3->c.level, BTREE_NODE_INTENT_LOCKED);
                        bch2_btree_path_level_init(trans, path2, n3);
 
                        n3->sib_u64s[0] = U16_MAX;
@@ -1574,13 +1542,20 @@ static int btree_split(struct btree_update *as, struct btree_trans *trans,
        } else {
                trace_and_count(c, btree_node_compact, c, b);
 
+               n1 = bch2_btree_node_alloc_replacement(as, trans, b);
+
+               if (keys) {
+                       btree_split_insert_keys(as, trans, path, n1, keys);
+                       BUG_ON(!bch2_keylist_empty(keys));
+               }
+
                bch2_btree_build_aux_trees(n1);
                bch2_btree_update_add_new_node(as, n1);
                six_unlock_write(&n1->c.lock);
 
                path1 = get_unlocked_mut_path(trans, path->btree_id, n1->c.level, n1->key.k.p);
                six_lock_increment(&n1->c.lock, SIX_LOCK_intent);
-               mark_btree_node_locked(trans, path1, n1->c.level, SIX_LOCK_intent);
+               mark_btree_node_locked(trans, path1, n1->c.level, BTREE_NODE_INTENT_LOCKED);
                bch2_btree_path_level_init(trans, path1, n1);
 
                if (parent)
@@ -1678,12 +1653,16 @@ bch2_btree_insert_keys_interior(struct btree_update *as,
 }
 
 /**
- * bch_btree_insert_node - insert bkeys into a given btree node
+ * bch2_btree_insert_node - insert bkeys into a given btree node
  *
- * @iter:              btree iterator
+ * @as:                        btree_update object
+ * @trans:             btree_trans object
+ * @path:              path that points to current node
+ * @b:                 node to insert keys into
  * @keys:              list of keys to insert
- * @hook:              insert callback
- * @persistent:                if not null, @persistent will wait on journal write
+ * @flags:             transaction commit flags
+ *
+ * Returns: 0 on success, typically transaction restart error on failure
  *
  * Inserts as many keys as it can into a given btree node, splitting it if full.
  * If a split occurred, this function will return early. This can only happen
@@ -1705,9 +1684,6 @@ static int bch2_btree_insert_node(struct btree_update *as, struct btree_trans *t
        BUG_ON(!as || as->b);
        bch2_verify_keylist_sorted(keys);
 
-       if (!(local_clock() & 63))
-               return btree_trans_restart(trans, BCH_ERR_transaction_restart_split_race);
-
        ret = bch2_btree_node_lock_write(trans, path, &b->c);
        if (ret)
                return ret;
@@ -1744,8 +1720,10 @@ split:
         * We could attempt to avoid the transaction restart, by calling
         * bch2_btree_path_upgrade() and allocating more nodes:
         */
-       if (b->c.level >= as->update_level)
+       if (b->c.level >= as->update_level) {
+               trace_and_count(c, trans_restart_split_race, trans, _THIS_IP_, b);
                return btree_trans_restart(trans, BCH_ERR_transaction_restart_split_race);
+       }
 
        return btree_split(as, trans, path, b, keys, flags);
 }
@@ -1801,8 +1779,8 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
 
        b = path->l[level].b;
 
-       if ((sib == btree_prev_sib && !bpos_cmp(b->data->min_key, POS_MIN)) ||
-           (sib == btree_next_sib && !bpos_cmp(b->data->max_key, SPOS_MAX))) {
+       if ((sib == btree_prev_sib && bpos_eq(b->data->min_key, POS_MIN)) ||
+           (sib == btree_next_sib && bpos_eq(b->data->max_key, SPOS_MAX))) {
                b->sib_u64s[sib] = U16_MAX;
                return 0;
        }
@@ -1835,7 +1813,7 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
                next = m;
        }
 
-       if (bkey_cmp(bpos_successor(prev->data->max_key), next->data->min_key)) {
+       if (!bpos_eq(bpos_successor(prev->data->max_key), next->data->min_key)) {
                struct printbuf buf1 = PRINTBUF, buf2 = PRINTBUF;
 
                bch2_bpos_to_text(&buf1, prev->data->max_key);
@@ -1877,9 +1855,7 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
 
        parent = btree_node_parent(path, b);
        as = bch2_btree_update_start(trans, path, level, false,
-                        BTREE_INSERT_NOFAIL|
-                        BTREE_INSERT_USE_RESERVE|
-                        flags);
+                                    BTREE_INSERT_NOFAIL|flags);
        ret = PTR_ERR_OR_ZERO(as);
        if (ret)
                goto err;
@@ -1910,7 +1886,7 @@ int __bch2_foreground_maybe_merge(struct btree_trans *trans,
 
        new_path = get_unlocked_mut_path(trans, path->btree_id, n->c.level, n->key.k.p);
        six_lock_increment(&n->c.lock, SIX_LOCK_intent);
-       mark_btree_node_locked(trans, new_path, n->c.level, SIX_LOCK_intent);
+       mark_btree_node_locked(trans, new_path, n->c.level, BTREE_NODE_INTENT_LOCKED);
        bch2_btree_path_level_init(trans, new_path, n);
 
        bkey_init(&delete.k);
@@ -1954,9 +1930,6 @@ err_free_update:
        goto out;
 }
 
-/**
- * bch_btree_node_rewrite - Rewrite/move a btree node
- */
 int bch2_btree_node_rewrite(struct btree_trans *trans,
                            struct btree_iter *iter,
                            struct btree *b,
@@ -1987,7 +1960,7 @@ int bch2_btree_node_rewrite(struct btree_trans *trans,
 
        new_path = get_unlocked_mut_path(trans, iter->btree_id, n->c.level, n->key.k.p);
        six_lock_increment(&n->c.lock, SIX_LOCK_intent);
-       mark_btree_node_locked(trans, new_path, n->c.level, SIX_LOCK_intent);
+       mark_btree_node_locked(trans, new_path, n->c.level, BTREE_NODE_INTENT_LOCKED);
        bch2_btree_path_level_init(trans, new_path, n);
 
        trace_and_count(c, btree_node_rewrite, c, b);
@@ -2025,6 +1998,7 @@ err:
 struct async_btree_rewrite {
        struct bch_fs           *c;
        struct work_struct      work;
+       struct list_head        list;
        enum btree_id           btree_id;
        unsigned                level;
        struct bpos             pos;
@@ -2034,6 +2008,7 @@ struct async_btree_rewrite {
 static int async_btree_node_rewrite_trans(struct btree_trans *trans,
                                          struct async_btree_rewrite *a)
 {
+       struct bch_fs *c = trans->c;
        struct btree_iter iter;
        struct btree *b;
        int ret;
@@ -2045,8 +2020,18 @@ static int async_btree_node_rewrite_trans(struct btree_trans *trans,
        if (ret)
                goto out;
 
-       if (!b || b->data->keys.seq != a->seq)
+       if (!b || b->data->keys.seq != a->seq) {
+               struct printbuf buf = PRINTBUF;
+
+               if (b)
+                       bch2_bkey_val_to_text(&buf, c, bkey_i_to_s_c(&b->key));
+               else
+                       prt_str(&buf, "(null");
+               bch_info(c, "%s: node to rewrite not found:, searching for seq %llu, got\n%s",
+                        __func__, a->seq, buf.buf);
+               printbuf_exit(&buf);
                goto out;
+       }
 
        ret = bch2_btree_node_rewrite(trans, &iter, b, 0);
 out:
@@ -2055,28 +2040,29 @@ out:
        return ret;
 }
 
-void async_btree_node_rewrite_work(struct work_struct *work)
+static void async_btree_node_rewrite_work(struct work_struct *work)
 {
        struct async_btree_rewrite *a =
                container_of(work, struct async_btree_rewrite, work);
        struct bch_fs *c = a->c;
+       int ret;
 
-       bch2_trans_do(c, NULL, NULL, 0,
-                     async_btree_node_rewrite_trans(&trans, a));
-       percpu_ref_put(&c->writes);
+       ret = bch2_trans_do(c, NULL, NULL, 0,
+                     async_btree_node_rewrite_trans(trans, a));
+       if (ret)
+               bch_err_fn(c, ret);
+       bch2_write_ref_put(c, BCH_WRITE_REF_node_rewrite);
        kfree(a);
 }
 
 void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
 {
        struct async_btree_rewrite *a;
-
-       if (!percpu_ref_tryget_live(&c->writes))
-               return;
+       int ret;
 
        a = kmalloc(sizeof(*a), GFP_NOFS);
        if (!a) {
-               percpu_ref_put(&c->writes);
+               bch_err(c, "%s: error allocating memory", __func__);
                return;
        }
 
@@ -2085,15 +2071,67 @@ void bch2_btree_node_rewrite_async(struct bch_fs *c, struct btree *b)
        a->level        = b->c.level;
        a->pos          = b->key.k.p;
        a->seq          = b->data->keys.seq;
-
        INIT_WORK(&a->work, async_btree_node_rewrite_work);
+
+       if (unlikely(!test_bit(BCH_FS_MAY_GO_RW, &c->flags))) {
+               mutex_lock(&c->pending_node_rewrites_lock);
+               list_add(&a->list, &c->pending_node_rewrites);
+               mutex_unlock(&c->pending_node_rewrites_lock);
+               return;
+       }
+
+       if (!bch2_write_ref_tryget(c, BCH_WRITE_REF_node_rewrite)) {
+               if (test_bit(BCH_FS_STARTED, &c->flags)) {
+                       bch_err(c, "%s: error getting c->writes ref", __func__);
+                       kfree(a);
+                       return;
+               }
+
+               ret = bch2_fs_read_write_early(c);
+               if (ret) {
+                       bch_err_msg(c, ret, "going read-write");
+                       kfree(a);
+                       return;
+               }
+
+               bch2_write_ref_get(c, BCH_WRITE_REF_node_rewrite);
+       }
+
        queue_work(c->btree_interior_update_worker, &a->work);
 }
 
+void bch2_do_pending_node_rewrites(struct bch_fs *c)
+{
+       struct async_btree_rewrite *a, *n;
+
+       mutex_lock(&c->pending_node_rewrites_lock);
+       list_for_each_entry_safe(a, n, &c->pending_node_rewrites, list) {
+               list_del(&a->list);
+
+               bch2_write_ref_get(c, BCH_WRITE_REF_node_rewrite);
+               queue_work(c->btree_interior_update_worker, &a->work);
+       }
+       mutex_unlock(&c->pending_node_rewrites_lock);
+}
+
+void bch2_free_pending_node_rewrites(struct bch_fs *c)
+{
+       struct async_btree_rewrite *a, *n;
+
+       mutex_lock(&c->pending_node_rewrites_lock);
+       list_for_each_entry_safe(a, n, &c->pending_node_rewrites, list) {
+               list_del(&a->list);
+
+               kfree(a);
+       }
+       mutex_unlock(&c->pending_node_rewrites_lock);
+}
+
 static int __bch2_btree_node_update_key(struct btree_trans *trans,
                                        struct btree_iter *iter,
                                        struct btree *b, struct btree *new_hash,
                                        struct bkey_i *new_key,
+                                       unsigned commit_flags,
                                        bool skip_triggers)
 {
        struct bch_fs *c = trans->c;
@@ -2129,11 +2167,11 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                                _THIS_IP_);
 
                BUG_ON(iter2.path->level != b->c.level);
-               BUG_ON(bpos_cmp(iter2.path->pos, new_key->k.p));
+               BUG_ON(!bpos_eq(iter2.path->pos, new_key->k.p));
 
                btree_path_set_level_up(trans, iter2.path);
 
-               bch2_btree_path_check_sort(trans, iter2.path, 0);
+               trans->paths_sorted = false;
 
                ret   = bch2_btree_iter_traverse(&iter2) ?:
                        bch2_trans_update(trans, &iter2, new_key, BTREE_TRIGGER_NORUN);
@@ -2154,12 +2192,7 @@ static int __bch2_btree_node_update_key(struct btree_trans *trans,
                trans->extra_journal_entries.nr += jset_u64s(new_key->k.u64s);
        }
 
-       ret = bch2_trans_commit(trans, NULL, NULL,
-                               BTREE_INSERT_NOFAIL|
-                               BTREE_INSERT_NOCHECK_RW|
-                               BTREE_INSERT_USE_RESERVE|
-                               BTREE_INSERT_JOURNAL_RECLAIM|
-                               JOURNAL_WATERMARK_reserved);
+       ret = bch2_trans_commit(trans, NULL, NULL, commit_flags);
        if (ret)
                goto err;
 
@@ -2193,7 +2226,7 @@ err:
 
 int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *iter,
                               struct btree *b, struct bkey_i *new_key,
-                              bool skip_triggers)
+                              unsigned commit_flags, bool skip_triggers)
 {
        struct bch_fs *c = trans->c;
        struct btree *new_hash = NULL;
@@ -2214,19 +2247,17 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
        if (btree_ptr_hash_val(new_key) != b->hash_val) {
                ret = bch2_btree_cache_cannibalize_lock(c, &cl);
                if (ret) {
-                       bch2_trans_unlock(trans);
-                       closure_sync(&cl);
-                       ret = bch2_trans_relock(trans);
+                       ret = drop_locks_do(trans, (closure_sync(&cl), 0));
                        if (ret)
                                return ret;
                }
 
-               new_hash = bch2_btree_node_mem_alloc(c, false);
+               new_hash = bch2_btree_node_mem_alloc(trans, false);
        }
 
        path->intent_ref++;
-       ret = __bch2_btree_node_update_key(trans, iter, b, new_hash,
-                                          new_key, skip_triggers);
+       ret = __bch2_btree_node_update_key(trans, iter, b, new_hash, new_key,
+                                          commit_flags, skip_triggers);
        --path->intent_ref;
 
        if (new_hash) {
@@ -2244,7 +2275,7 @@ int bch2_btree_node_update_key(struct btree_trans *trans, struct btree_iter *ite
 
 int bch2_btree_node_update_key_get_iter(struct btree_trans *trans,
                                        struct btree *b, struct bkey_i *new_key,
-                                       bool skip_triggers)
+                                       unsigned commit_flags, bool skip_triggers)
 {
        struct btree_iter iter;
        int ret;
@@ -2265,7 +2296,8 @@ int bch2_btree_node_update_key_get_iter(struct btree_trans *trans,
 
        BUG_ON(!btree_node_hashed(b));
 
-       ret = bch2_btree_node_update_key(trans, &iter, b, new_key, skip_triggers);
+       ret = bch2_btree_node_update_key(trans, &iter, b, new_key,
+                                        commit_flags, skip_triggers);
 out:
        bch2_trans_iter_exit(trans, &iter);
        return ret;
@@ -2284,8 +2316,9 @@ void bch2_btree_set_root_for_read(struct bch_fs *c, struct btree *b)
        bch2_btree_set_root_inmem(c, b);
 }
 
-void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
+static int __bch2_btree_root_alloc(struct btree_trans *trans, enum btree_id id)
 {
+       struct bch_fs *c = trans->c;
        struct closure cl;
        struct btree *b;
        int ret;
@@ -2297,7 +2330,7 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
                closure_sync(&cl);
        } while (ret);
 
-       b = bch2_btree_node_mem_alloc(c, false);
+       b = bch2_btree_node_mem_alloc(trans, false);
        bch2_btree_cache_cannibalize_unlock(c);
 
        set_btree_node_fake(b);
@@ -2326,6 +2359,12 @@ void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
 
        six_unlock_write(&b->c.lock);
        six_unlock_intent(&b->c.lock);
+       return 0;
+}
+
+void bch2_btree_root_alloc(struct bch_fs *c, enum btree_id id)
+{
+       bch2_trans_run(c, __bch2_btree_root_alloc(trans, id));
 }
 
 void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
@@ -2338,7 +2377,7 @@ void bch2_btree_updates_to_text(struct printbuf *out, struct bch_fs *c)
                       as,
                       as->mode,
                       as->nodes_written,
-                      atomic_read(&as->cl.remaining) & CLOSURE_REMAINING_MASK,
+                      closure_nr_remaining(&as->cl),
                       as->journal.seq);
        mutex_unlock(&c->btree_interior_update_lock);
 }
@@ -2364,20 +2403,15 @@ bool bch2_btree_interior_updates_flush(struct bch_fs *c)
        return ret;
 }
 
-void bch2_journal_entries_to_btree_roots(struct bch_fs *c, struct jset *jset)
+void bch2_journal_entry_to_btree_root(struct bch_fs *c, struct jset_entry *entry)
 {
-       struct btree_root *r;
-       struct jset_entry *entry;
+       struct btree_root *r = bch2_btree_id_root(c, entry->btree_id);
 
        mutex_lock(&c->btree_root_lock);
 
-       vstruct_for_each(jset, entry)
-               if (entry->type == BCH_JSET_ENTRY_btree_root) {
-                       r = &c->btree_roots[entry->btree_id];
-                       r->level = entry->level;
-                       r->alive = true;
-                       bkey_copy(&r->key, &entry->start[0]);
-               }
+       r->level = entry->level;
+       r->alive = true;
+       bkey_copy(&r->key, &entry->start[0]);
 
        mutex_unlock(&c->btree_root_lock);
 }
@@ -2397,15 +2431,15 @@ bch2_btree_roots_to_journal_entries(struct bch_fs *c,
 
        mutex_lock(&c->btree_root_lock);
 
-       for (i = 0; i < BTREE_ID_NR; i++)
-               if (c->btree_roots[i].alive && !test_bit(i, &have)) {
-                       journal_entry_set(end,
-                                         BCH_JSET_ENTRY_btree_root,
-                                         i, c->btree_roots[i].level,
-                                         &c->btree_roots[i].key,
-                                         c->btree_roots[i].key.u64s);
+       for (i = 0; i < btree_id_nr_alive(c); i++) {
+               struct btree_root *r = bch2_btree_id_root(c, i);
+
+               if (r->alive && !test_bit(i, &have)) {
+                       journal_entry_set(end, BCH_JSET_ENTRY_btree_root,
+                                         i, r->level, &r->key, r->key.k.u64s);
                        end = vstruct_next(end);
                }
+       }
 
        mutex_unlock(&c->btree_root_lock);
 
@@ -2419,7 +2453,7 @@ void bch2_fs_btree_interior_update_exit(struct bch_fs *c)
        mempool_exit(&c->btree_interior_update_pool);
 }
 
-int bch2_fs_btree_interior_update_init(struct bch_fs *c)
+void bch2_fs_btree_interior_update_init_early(struct bch_fs *c)
 {
        mutex_init(&c->btree_reserve_cache_lock);
        INIT_LIST_HEAD(&c->btree_interior_update_list);
@@ -2427,11 +2461,20 @@ int bch2_fs_btree_interior_update_init(struct bch_fs *c)
        mutex_init(&c->btree_interior_update_lock);
        INIT_WORK(&c->btree_interior_update_work, btree_interior_update_work);
 
+       INIT_LIST_HEAD(&c->pending_node_rewrites);
+       mutex_init(&c->pending_node_rewrites_lock);
+}
+
+int bch2_fs_btree_interior_update_init(struct bch_fs *c)
+{
        c->btree_interior_update_worker =
                alloc_workqueue("btree_update", WQ_UNBOUND|WQ_MEM_RECLAIM, 1);
        if (!c->btree_interior_update_worker)
-               return -ENOMEM;
+               return -BCH_ERR_ENOMEM_btree_interior_update_worker_init;
 
-       return mempool_init_kmalloc_pool(&c->btree_interior_update_pool, 1,
-                                        sizeof(struct btree_update));
+       if (mempool_init_kmalloc_pool(&c->btree_interior_update_pool, 1,
+                                     sizeof(struct btree_update)))
+               return -BCH_ERR_ENOMEM_btree_interior_update_pool_init;
+
+       return 0;
 }